Connect Four

How to Play

1. Players alternate choosing one of the seven columns.
2. A disc falls to the lowest empty cell in that column.
3. The first player to connect four discs in a horizontal, vertical or diagonal line wins immediately.
4. A full column cannot be selected.
5. If the entire board fills without a four-in-a-row, the game ends in a draw.

Threats and Forks

A strong move often creates a threat: a square that would win on your next turn. Even stronger is a fork, where two different winning moves are available next turn and the opponent can block only one. Because discs fall downward, every future threat also depends on whether the supporting cells beneath it can be filled safely.

Strategy Tips

• The center column participates in more possible four-in-a-row lines than an edge column.
• Always check whether the opponent can win immediately before pursuing your own longer plan.
• Avoid moves that give the opponent the supporting square needed for a winning diagonal.
• On hard difficulty, create multiple threats instead of relying on a single obvious line.

Game-Theory Connection

Connect Four is a deterministic perfect-information game. It is a compact setting for Minimax reasoning, tactical threat detection, alpha-beta pruning and heuristic evaluation. The gravity rule makes the action space especially interesting because not every empty square is immediately playable.